JP2019194222A - Method and system for providing transalkylation supply flow by separating flow in aromatic compound composition facility - Google Patents

Abstract

To provide a method and a system for manufacturing at least one kind of xylene isomer.SOLUTION: The method for manufacturing a xylene isomer includes sending a first flow to a first side part of a divided shell fractionator column and sending a second flow to other side part of the column. The first flow has a higher ratio of methyl/Calkyl substituted Caromatic compound than the second flow. A tower understream is separated from one side part and is sent to a transalkylation zone as a supply flow.SELECTED DRAWING: Figure 1

Description

  [0001] This application is priority to US Provisional Applications 61 / 860,563 and 61 / 860,571, filed July 31, 2013, the contents of which are hereby incorporated by reference in their entirety. Insist.

[0002] Xylene isomers are produced in large quantities from petroleum as a feedstock for a variety of important industrial chemicals. Of the xylene isomers, para-xylene, the primary feedstock for polyesters that continues to possess high growth rates from large-scale demand, is the most important. Ortho-xylene is used to produce phthalic anhydride, which is supplied to a large but relatively mature market. Meta-xylene is used in smaller but growing quantities for products such as plasticizers, azo dyes, and wood preservatives. Ethylbenzene generally is present in xylene mixtures, although sometimes recovered for styrene production, generally are considered to be more undesirable components of C ₈ aromatics.

[0003] Among aromatic hydrocarbons, the overall importance of xylenes competes with that of benzene as a feedstock for industrial chemicals. Xylenes and benzene are produced from petroleum by naphtha reforming, but this is not sufficient to meet demand, and therefore other hydrocarbons to increase the yield of xylenes and benzene. Need to be converted. Often, either the production of benzene by dealkylation of toluene, or selectively by disproportionation to produce benzene and C ₈ aromatics, is now recovered individual xylene isomers.

[0004] Flow chart of aromatic compound complex is Meyers, Handbook of Petroleum Refining
Processes, 2nd edition, 1997, McGraw-Hill (incorporated herein by reference).

Meyers, Handbook of Petroleum Refining Processes, 2nd edition, 1997, McGraw-Hill

[0005] Traditional aromatics complex may send a toluene transalkylation zone, to produce the desired xylene isomers by transalkylation of toluene by A ₉ components. A ₉ component is present in both the reformate bottom stream and the transalkylation effluent. A ₉ component also might to some extent also present in the isomerization effluent. At present, efforts to separate based on the A ₉ components to their source or the particular structure is not performed.

[0006] According to one aspect, a method for producing one or more xylenes, first containing xylenes and C ₉ aromatics in a first ratio of methyl / C ₂₊ alkyl-substituted C ₉ aromatics Flow to one side of a split shell fractionation column that includes a vertical baffle that separates one side from the other. This method, the second stream comprising a first xylenes in the second ratio of the lower-methyl / C ₂₊ alkyl-substituted C ₉ aromatics than the ratio and C ₉ aromatics, split shell fractionation column Further comprising sending to the other side. This method involves separating a common overhead stream containing xylenes from a split shell fractionation column. The method also includes separating the first bottoms stream from one side of the split shell fractionation column and separating the second bottoms stream from the other side of the split shell fractionation column.

[0007] According to one aspect, a method for producing one or more xylenes, a first stream comprising at least a portion of the transalkylation zone effluent stream comprising C ₉ aromatics, transalkylation effluent Sending to the transalkylation effluent side of a split shell fractionation column containing vertical baffles separating the stream side from the reformate side. This method also a second stream comprising at least a portion of the reformate stream comprising C ₉ aromatics, including sending the reformate side of the split shell fractionation column. This method involves separating a common overhead stream containing xylenes from a split shell fractionation column. This method, the transalkylation effluent stream side bottoms stream comprising C ₉ aromatics from the transalkylation effluent side of the split shell fractionation column are separated and C ₉ aromatics from reformate side of the split shell fractionation column The method further comprises separating the reformate side bottom stream containing the compound.

[0008] FIG. 1 illustrates an aromatic compound complex. [0009] FIG. 2 illustrates a high energy efficiency aromatic compound complex. [0010] FIG. 3 illustrates an aromatic compound complex according to various aspects. [0011] FIG. 4 illustrates a high energy efficiency aromatic compound complex according to various aspects.

  [0012] Corresponding reference characters indicate corresponding components throughout the several views. Those skilled in the art will recognize that the components in the drawings are shown for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some members in the drawings may be exaggerated relative to other members to help improve understanding of various aspects of the invention. In addition, conventional but well-understood components that are useful or necessary in commercially feasible embodiments are often used to promote a more unobstructed view of these various aspects of the invention. Not shown.

[0013] The following description should not be construed in a limiting sense, but is made merely for the purpose of describing general principles of representative form. The scope of the invention is determined with reference to the claims.
[0014] In the current aromatics complex, and sent to the transalkylation zone as a mixture of different sources materials A ₉ components without considering A ₉ one alkyl group, based on the alkyl group A ₉ There is no effort to separate the species. Since ethyl and higher alkyl groups are cleaved from the aromatic ring to form less valuable benzene and fuel gas, the desired A ₈ component depends on the methyl substituted A ₉ species used as feed to the transalkylation zone. It was confirmed that the yield of was increased. In this regard, a stream having a higher amount of C ₂₊ ethyl-substituted aromatic compounds, comprising separating and maintained as a separate stream with a greater amount of methyl-substituted C ₉ aromatics, one or more xylene An apparatus and method for manufacturing the same is provided. Because this method and apparatus uses a split shell fractionation column, these streams can be separated without significantly increasing capital or energy requirements. Advantageously, when an aromatic compound complex is combined with a dedicated gasoline production facility, C ₉ aromatics with C ₂₊ alkyl groups can be sent to the gasoline pool without further processing, thereby providing paraxylene. The amount of by-product benzene and fuel gas is limited while increasing production.

[0015] feed to the present process generally the general _formula: C _{6 H} in _{(6-n) R} n _(wherein, n is an integer from 0 to 5, each R, CH in any combination ₃ , C ₂ H ₅ , C ₃ H ₇ , or C ₄ H ₉ ). The aromatics-rich feed to the process of the present invention includes, without limitation, catalytic reforming, light olefins and heavier aromatics-rich byproducts (often referred to as “pigas” in the gasoline range) From various sources such as steam pyrolysis of naphtha, distillate or other hydrocarbons to obtain), and contact or pyrolysis of distillate and heavy oil to obtain products in the gasoline range Can be guided. Products from pyrolysis or other cracking operations generally remove the sulfur, olefins, and other compounds that adversely affect and / or damage the product quality of the catalyst or adsorbent used in the present invention. And then hydrogenating according to processes well known in the industry prior to loading into the complex. Light cycle oils from catalytic cracking can also be beneficially hydrotreated and / or hydrocracked according to known techniques to obtain gasoline range products; hydrotreating is preferably rich in aromatics Also includes catalytic reforming to obtain a feed stream. When the feed stream is catalytic reformate, the reformer preferably operates at high severity to achieve high aromatic yield with low concentrations of non-aromatic compounds in the product.

[0016] FIG. 1 is a simplified flow diagram of a representative aromatic compound processing complex of the prior art aimed at producing at least one xylene isomer. This complex can handle a feed stream rich in aromatics derived, for example, from catalytic reforming in the reforming zone 6. The reforming zone generally includes a reforming unit 4 that receives the feed stream via conduit 2. The reforming unit usually includes a reforming catalyst. Usually such streams are also treated to remove olefinic compounds and light fractions such as butanes, and lighter hydrocarbons, preferably pentanes, but such removal is a broad form of the invention. It is not essential for implementation and is not shown. Feed stream comprising aromatic compounds are benzene include toluene, and C ₈ aromatics, usually contain more luxury aromatics and aliphatic hydrocarbons such as naphthenes.

[0017] feedstream through conduit 10, through a heat exchanger 12 is sent to re formate splitter 14, distilled to a stream comprising aromatics C ₈ and heavier, overhead through conduit 18 It is separated from toluene and lighter hydrocarbons recovered from the waste water and discharged as a bottom stream into the conduit 16 via the bottom outlet 15. Toluene and lighter hydrocarbons are sent to the extractive distillation process unit 20 to separate the predominantly aliphatic raffinate in conduit 21 from the benzene-toluene aromatic stream in conduit 22. The aromatics stream in conduit 22 is fed into conduit 24 in benzene column 23 along with the stripped transalkylation product in conduit 45 and the overhead stream from the paraxylene finishing column in conduit 57. And the toluene and heavier aromatics stream in conduit 25 (which is sent to toluene column 26). Toluene is recovered from the top of the column into conduit 27, which can be partially or wholly sent to transalkylation unit 40 as shown and discussed below.

[0018] The bottom stream from toluene column 26 through conduit 28, the bottom stream from the re formate splitter in conduit 16 after processing by clay treatment apparatus 17, and recirculation C ₈ aromatics in the conduit 65 And sent to the fractionator 30 together. The fractionator 30 contains concentrated C ₈ aromatics as a top stream in conduit 31, C ₉ , C ₁₀ as a bottom stream in conduit 32, and a heavier aromatic compound. Separate from the boiling stream. This bottoms stream is sent to heavy fraction column 70 in conduit 32. The heavy aromatics column provides a top stream containing at least a portion of C ₉ and C ₁₀ aromatics into conduit 71 to provide higher boiling compounds, primarily C ₁₁ and higher alkyl aromatics. Is discharged as a bottom stream through a conduit 72.

[0019] The _{C9 +} aromatics from the heavy column in conduit 71 contain a transalkylation catalyst known in the art, and a transalkylation product comprising benzene from _{C11 +} aromatics and xylenes. As a feed stream to the transalkylation reactor 40 to be produced as an object, it is mixed with the overhead stream containing toluene contained in the conduit 27. The transalkylation product in conduit 41 is stripped in stripper 42 to provide gas in conduit 43 and C ₆ and lighter hydrocarbons (which are used to recover light aromatics and purify benzene. In order to return to extractive distillation 20 through conduit 44). The bottom stream from the stripper is sent to benzene column 23 in conduit 45 to recover the benzene product and unconverted toluene.

[0020] The C ₈ aromatics overhead stream provided by fractionator 30 includes para-xylene, meta-xylene, ortho-xylene, and ethylbenzene, which passes through conduit 31 to para-xylene separation process 50. The separation process is preferably operated by adsorption with a desorbent to feed a mixture of paraxylene and desorbent through conduit 51 to the extract column 52 so that paraxylene is fed from the return desorbent in conduit 54 to conduit 53. Para-xylene is purified in finishing column 55 to obtain para-xylene product through conduit 56 and light material returned to benzene column 23 through conduit 57. Non-equilibrium mixture of C ₈ aromatics raffinate and desorbent from separation process 50 may send through a conduit 58 to a raffinate column 59, raffinate, from the return desorbent in conduit 61 to isomerization in conduit 60 To separate.

[0021] A raffinate comprising a non-equilibrium mixture of xylene isomers and ethylbenzene is sent to isomerization reactor 62 through conduit 60. And isomerizing the raffinate in reactor 62 containing isomerization catalyst, giving the product close to the equilibrium concentration of C ₈ aromatics isomers. Products, through the conduit 63 is sent to de-heptane of 64, removed hydrocarbons C ₇ and lighter in the bottom stream, sent to the xylene column 30 through conduit 65, from C ₈ aromatics which are isomerized separating the C ₉ and heavier material. Overhead liquid from the de-heptane of 64 be sent to the stripper (66), the C ₆ and C ₇ material sent to the extractive distillation unit 20 through conduit 68 to recover the organic valuable substances of benzene and toluene, conduit A light material top stream is removed through 67.

[0022] As will be appreciated by those skilled in the art, there are many possible variations of this scheme within the known art. For example, the entire C ₆ -C ₈ reformate or only the benzene-containing portion can be subjected to extraction. Paraxylene, than adsorption can be recovered from the C ₈ aromatics mixture by crystallization. Meta-xylene and para-xylene can be recovered from the C ₈ aromatic compound mixture by adsorption, and ortho-xylene can be recovered by fractional distillation. Alternatively, the C ₉ and heavier streams or heavy aromatics streams can be treated with solvent extraction using polar solvents or solvent distillation, or stripping using steam or other media to achieve high concentration. The aromatics are separated from the C ₉₊ recycle stream to transalkylation as a residue stream. In some cases, the entire heavy aromatics stream can be processed directly in the transalkylation unit. The present invention is useful in these and other variations of aromatics processing schemes, some forms of which are described in US-6,740,788 (incorporated herein by reference). .

  [0023] Referring to FIG. 2, there is shown another representative aromatic compound complex that has been modified to improve energy efficiency. This high energy efficiency aromatic compound complex is described in US Patent Publication 2012/0048720, which is hereby incorporated by reference in its entirety. For ease of reference, a parallel numbering system is used in FIGS. 1 and 2 and similar components are not described in detail here. It should be noted that several variations of process flow and equipment are possible in this complex, and this is contemplated by the present invention. The high energy efficiency aromatic compound complex includes first and second xylene columns 130 and 133. In this example, the first xylene column 130 is a low pressure column, while the second xylene column is a high pressure column. In the reforming zone 106, the feed stream is routed through conduit 102 to a reforming unit 104 containing the reforming catalyst known in the art and described above in connection with FIG. Reformate is sent to reformate splitter 114 through conduit 110 and through heat exchangers 112 and 113 that raise the temperature of the feed stream. Heat exchange can be fed from the net paraxylene product and the recovered paraxylene separation process recovery desorbent through conduits 212 and 213, respectively, as discussed later in this section.

[0024] As seen in FIG. 1, the aromatic compound of C ₈ and heavier is discharged as bottoms stream via conduit 116 via bottom stream outlet, whereas, toluene is recovered from the top through conduit 118 and Lighter hydrocarbons are sent to the extractive distillation processing unit 120 to separate the predominantly aliphatic raffinate in conduit 121 from the benzene-toluene aromatics stream in conduit 122. The aromatics stream in conduit 122 is fed into the fractionator 123 along with the stripped transalkylation product in conduit 144 and the overhead stream from the paraxylene finishing column in conduit 157. A benzene stream in 124 and a stream of toluene and heavier aromatics in conduit 125 (which is sent to toluene column 126). Toluene is recovered in conduit 127 from the top of this column and can be partially or wholly sent to transalkylation unit 140 as shown and discussed below.

[0025] The bottom stream from the toluene column 126 is passed through conduit 128 through the bottom of the bottom stream from the reformate splitter in conduit 116 after being treated by the clay processor 117, and recirculated C ₈ aromatics in conduit 138. Together with the low pressure xylene column 130. Other C ₈ aromatics stream which has a substantial content of aromatics of C ₉ and heavier includes a flow resulting from a source of the complex external also can be processed in the column; whole Depending on the overall energy balance, a portion of the deheptanizer bottoms stream in stream 165 can also be included. The low pressure xylene column is a high boiling stream containing concentrated C ₈ aromatics as the top stream in conduit 131, C ₉ , C ₁₀ as the bottom stream in conduit 132, and heavier aromatics. Separate from.

At the same time, the isomerized C ₈ aromatics stream is sent through conduit 165 to a high pressure second xylene column 133. This is characterized as a lower boiling feed stream containing heavy material that is subjected to a lower concentration of cracking than the feed stream to the column 130, and thus the column pressure can be increased to achieve energy savings. Also included in the feed to this column are C ₉ and other C ₈ aromatics containing streams with a similarly low content of heavier aromatics, including streams derived from sources external to the complex. Can be made. The second xylene column separates the second C ₈ aromatics stream from the second C ₉ and heavier stream in conduit 139 as a top stream in conduit 134. At least a portion of the overhead vapor from the high pressure xylene column in conduit 134 is preferably used to reboil the low pressure xylene column 130 in reboiler 135 and sent as condensate to xylene separation process 150 in conduit 136. And refluxed to the column 133 (not shown). Further, the overhead stream in conduit 134 is preferably used to supply energy to the reboiler of extraction column 152, as well as other such equipment described below or apparent to those skilled in the art.

[0027] The C ₉₊ bottom stream sent to reboiler 137 is a heavy aromatic compound via one or both of the stream before the reboiler in conduit 270 and the heated stream from the reboiler in conduit 259, respectively. Energy for reboiling one or both of column 170 and raffinate column 159 can be supplied; the bottom stream after heat exchange is sent to heavy aromatics column 170. Other similar heat exchange facilities will be apparent to those skilled in the art. The net bottoms stream in conduit 138 may normally be routed through column 130 or mixed directly with the flow in conduit 132 to heavy fraction column 170 in conduit 139. The heavy column column provides a top stream in conduit 171 containing at least a portion of C ₉ and C ₁₀ aromatics, with higher boiling compounds, primarily C ₁₁ and higher alkyl aromatics, Discharge through conduit 172 as a bottom stream. This column can be reboiled by the bottom stream of the xylene column in conduit 270 as discussed above. The overhead steam from columns 130 and 170 can also generate steam through conduits 230 and 271, respectively, as shown, and the condensate is returned to the respective columns or net in streams 131 or 171 respectively. It is supplied as one of the tower top streams.

[0028] C ₉₊ aromatics from the heavy column in conduit 171 are contained in conduit 127 as a feed stream to transalkylation reactor 140 that produces transalkylation products including xylenes. Mix with the overhead stream containing toluene. The transalkylation product in conduit 141 is stripped in stripper 142 to remove gas into conduit 143, and C ₇ and lighter liquids, which are passed through conduit 144 through isomerate stripper 166. Returned to extractive distillation 120 for recovery of light aromatics after stabilization within. The bottom stream from the stripper is sent to benzene column 123 in conduit 145 to recover the benzene product and unconverted toluene.

[0029] First and second C ₈ aromatics streams, including para-xylene, meta-xylene, ortho-xylene, and ethylbenzene, provided by xylene columns 130 and 133, are passed through conduits 131 and 136 to a xylene isomer separation process 150. Send to. Although the description herein is applicable to the recovery of one or more xylene isomers other than paraxylene, this description is presented with respect to paraxylene for ease of understanding. The separation process is operated by a moving bed adsorption process that feeds a first mixture of paraxylene and desorbent through conduit 151 to extract column 152, thereby passing paraxylene from return desorbent in conduit 154 through conduit 153. To separate. The extract column 152 is preferably operated at a pressure increase of at least 300 kPa, more preferably 500 kPa or more, so that the overhead stream from the column is deheptaneated via conduit 256 or finished column 155 or conduit 265. Ensure that the generator 164 is at a temperature sufficient to reboil. The heat supplied for the reboiling operation through conduits 256 and 265 concentrates the extract in these streams, which refluxes to column 152 (not shown) or is net in conduit 153. Either or both are sent to the finishing column 155 as a stream. Para-xylene is purified in finishing column 155 to obtain a para-xylene product through conduit 156 and a light material that is returned to benzene column 123 through conduit 157.

[0030] A second mixture of raffinate and desorbent as a non-equilibrium blend of C ₈ aromatics from separation process 150 is sent through conduit 158 to raffinate column 159 to send the raffinate to isomerization in conduit 160. Separate from the return desorbent in conduit 161. The raffinate column can be operated at higher pressures to produce steam through conduit 260 or to exchange heat in other areas of the complex; the liquid condensed from such heat exchange is directed to the raffinate column. It functions either as reflux or as a net overhead stream in conduit 160. The recovered desorbent in conduits 154 and 161 and the net finished column bottoms stream can heat the input feed stream in conduit 110 via conduits 213 and 212, respectively. In high energy-efficiency aromatics complex, the first fractionation column is lower the first C ₈ aromatics stream is driving at a pressure of the first C ₉ and heavier aromatics stream The second fractionation column can be operated at elevated pressure to separate the second C ₈ aromatics stream from the second C ₉ and heavier aromatics stream. . In this regard, the overhead stream from the second column can be recycled to supply heat to the reboiler of the first column. The low pressure is typically between 100 and 800 kPa, and the pressure increase is selected to allow heat transfer from the first column to the second column, and is usually at least 400 kPa higher than the low pressure.

[0031] The flow to the second column is less than 10 wt% _{C9 +} aromatics, more frequently less than 5 wt% _{C9 +} aromatics, more frequently less than 2 wt% _{C9 +} aromatics. Group compounds may be included. In the complex, the second fractionation column can also be operated at a pressure that allows the top stream to provide heat to produce steam useful in the associated processing complex. Furthermore, the C ₈ aromatics fractionator, it is possible to include more than two columns constituting a further heat exchanger between the top stream and the reboiler same form as above described.

[0032] Referring now to FIG. 3, an aromatic compound complex and process according to one aspect is shown and described. As shown in FIG. 3, according to this configuration, the xylene fractionation column includes a split shell fractionation column 330. This includes a baffle 333 extending from the bottom of the column and dividing the tray section of the fractionation column into two sides. The baffle extends to a height lower than the total height of the split shell fractionation column so that a common overhead stream can be recovered from above the baffle. The first stream is introduced into the first side 305 of the baffle 333 of the split shell fractionation column 330. The second stream is introduced into the second side 310 of the baffle 333 of the column 330. According to one approach, the first stream has a molar ratio of high methyl / C ₂₊ alkyl substituted C ₉ and C ₁₀ aromatics than the second stream, thus higher methyl / phenyl ratio. According to one approach, the first flow is between 2.0 and 3.0, in other examples between 1.5 and 3.5, in other examples 1.0 to 4.0. Having a ratio of methyl / phenyl groups. On the other hand, according to one example, the second flow is between 1.5 and 2.5, in other examples between 1.0 and 3.0, in other examples 0.5 to 2.5. Having a methyl / phenyl ratio of between 3.5.

[0033] In the example shown in FIG. 3, the first stream includes a portion of the transalkylation zone effluent. The transalkylation zone effluent can be processed and separated, such as by fractionation, before being introduced into the split shell fractionation column 330. In one approach, the first stream comprises at least a portion of the bottom stream from the toluene column 26 that is routed through line 28 to the inlet at the first side 305 of the split shell fractionation column. The second stream can include a reformate bottom stream portion, such as a bottom stream from reformate splitter 14 that is routed through line 16. The reformate bottom stream can be processed by the clay processor 17 or the like before being introduced into the second side 310 of the split shell fractionation column 330. Toluene column bottoms stream, it was confirmed that a high ratio of methyl / C ₂₊ alkyl-substituted C ₉ aromatics than reformate bottoms stream. The baffle 333 extends above both the levels of the feed inlets 315 and 320 and the normal operating liquid level of the split shell fractionation column 330 to prevent liquid from overflowing the baffle 333 and mixing. .

  [0034] A common overhead stream from a split shell fractionation column 330 containing mixed xylenes is sent through a conduit 31 to a paraxylene isomer separation zone to separate paraxylene as described above with respect to FIG. From xylene isomers and ethylbenzene.

[0035] Since the baffle 333 extends from the bottom of the split shell fractionation column 330 to a height above the normal operating liquid level of the column, the liquid tower bottom stream (transalkylation effluent from the first side 305). ) And the second liquid column bottom stream (reformate) from the second side 310 are kept separate. Transalkylation effluent side 3 of split shell fractionation column 330
The bottom stream from 05 is discharged as a first xylene column bottom stream through outlet 338 and sent to transalkylation reactor 40 in transalkylation zone 340 through conduit 71. As shown in FIG. 3, the bottom stream on the transalkylation side is sent to the inlet 341 of the transalkylation reactor 40. The transalkylation effluent bottoms stream can be further processed before being sent to the transalkylation zone 340. For example, as shown in FIG. 3, the transalkylation side bottoms stream can be sent through conduit 331 to heavy aromatic hydrocarbon fractionation column 70. In this regard, C ₉ and C ₁₀ aromatics can be withdrawn from the fractionation column 70 as overhead and sent to the transalkylation reactor 40. _Heavier compounds such as C ₁₁₊ aromatics can be discharged through conduit 72 as a bottom stream. The heavy aromatics fractionation column bottoms stream can be sent to other locations, for example, to blend with a gasoline pool if the aromatic compound complex is integrated with a refinery. The other part of the transalkylation effluent side column bottom stream can be routed through conduit 335 to reboiler 336 and back to first side 305 of split shell fractionation column 330.

[0036] According to one form, the bottoms stream from the reformate side 310 of the split shell fractionation column 330 is discharged through the reformate side bottom outlet 339 and sent to a destination other than the transalkylation zone 340. In one approach, as shown in FIG. 3, if the aromatic compound complex is integrated with a larger refining facility, the reformate side bottom stream is fed through line 332 to the gasoline pool or refining or petrochemical plant. Can be sent to other hydrocarbon streams. Since the bottom _stream mainly contains _{C9 +} aromatics, it is particularly well suited for blending into a gasoline pool. As shown in FIG. 3, other portions of the reformate side bottoms stream can be sent to reboiler 334 through conduit 337 and returned to reformate side 310 of split shell fractionation column 330.

[0037] As shown in FIG. 3, an A ₈₊ stream containing isomerized xylenes is processed in isomerization reactor 62 and separated in deheptanizer 64. C ₉ aromatics de heptane equalizer column in stream from the isomerization zone 362 is typically similar to the transalkylation zone effluent stream, high methyl / C ₂₊ alkyl-substituted C ₉ aromatics than the reformate bottoms stream Having a ratio of compounds. According to one form, at least a portion of the first stream can include at least a portion of the deheptanizer bottoms stream. In this regard, the deheptanizer bottoms stream can be discharged through outlet 364 and sent through conduit 65 to the first (transalkylation) side 305 of the split shell fractionation column. This stream can be introduced into the first side 305 of the split shell fractionation column in addition to or in place of the transalkylation zone effluent described above. If both streams are sent to the first side 305 of the xylene fractionation column 330, they can be sent separately through the separate inlets into the first side 305, or as shown in FIG. They can be mixed and introduced together through a common inlet 315. Regardless of how the isomerization zone bottoms stream is introduced into the split shell fractionation column 330, the inlet is from the top of the baffle 333 to suppress liquid overflow and mixing as described above. It should be noted that must also be placed below.

[0038] Referring now to FIG. 4, a high energy efficiency aromatic compound complex and process incorporating a split shell fractionation column according to one aspect is shown. As shown in FIG. 4, according to this embodiment, the first xylene fractionation column includes a split shell fractionation column 430. The split shell fractionation column includes a baffle 433 that extends from the bottom of the column and divides the tray section of the fractionation column 430 into two sides. The baffle extends to a height lower than the total height of the split shell fractionation column so that a common overhead stream can be recovered from above the baffle. The first stream is introduced into the first side 405 of the baffle 433 of the split shell fractionation column 430. The second stream is introduced into the second side 410 of the baffle 433 of the column 430. According to one approach, the first stream has a specific, hence higher-methyl / phenyl ratio of high methyl / C ₂₊ alkyl-substituted C ₉ aromatics than the second stream. According to one approach, the first flow is between 2.0 and 3.0, in other examples between 1.5 and 3.5, in other examples 1.0 to 4.0. Having a ratio of methyl / phenyl groups. On the other hand, according to one example, the second flow is between 1.5 and 2.5, in other examples between 1.0 and 3.0, in other examples 0.5 to 2.5. Having a methyl / phenyl ratio of between 3.5.

[0039] In the example shown in FIG. 4, the first stream includes a portion of the transalkylation zone effluent. The transalkylation zone effluent can be processed and separated, such as by fractional distillation, before being introduced into the split shell fractionation column 430. In one approach, the first stream includes at least a portion of the bottom stream from the toluene column 126 that is routed through line 128 to the inlet 415 at the first side 405 of the split shell fractionation column 430. The second stream can include a reformate bottom stream portion, such as a bottom stream from the reformate splitter 114 sent through line 116. The reformate bottoms stream can be processed by a clay processor 117 or the like before being introduced into the second side 410 of the split shell fractionation column 430. Toluene column bottoms stream, it was confirmed that a ratio of greater than Li formate splitter bottoms stream methyl / C ₂₊ alkyl-substituted C ₉ aromatics. The baffle 433 extends above both the levels of the feed inlets 415 and 420 and the normal operating liquid level of the split shell fractionation column 430 to prevent liquid from overflowing the baffle 433 and mixing. .

  [0040] A common overhead stream from split shell fractionation column 430 containing mixed xylenes is sent through conduit 131 to paraxylene isomer separation unit 150 to provide paraxylene as described above with respect to FIG. Separate from other xylene isomers and ethylbenzene.

[0041] Since the baffle 433 extends from the bottom of the split shell fractionation column 430 to a height above the normal operating liquid level of the column, the liquid column bottom stream (or transalkylation effluent from the first side 405). Stream) and the liquid bottoms stream (or reformate) from the second side 410 are kept separate. The bottom stream from the transalkylation effluent side 405 of split shell fractionation column 430 is discharged as a transalkylation effluent bottom stream through outlet 439, at least a portion of which is passed to inlet 441 to transalkylation reactor 140. Sent. The transalkylation side bottoms stream can be further processed or separated before being sent to the transalkylation zone 440. For example, as shown in FIG. 4, the transalkylation side bottoms stream can be sent through an inlet 471 to a heavy aromatic hydrocarbon fractionation column 170. In this regard, C ₉ and C ₁₀ aromatics are withdrawn as overhead from the fractionation column 170 through outlet 472 and sent to the transalkylation reactor 140. _Heavier compounds such as C ₁₁₊ aromatics can be discharged through conduit 172 as a bottom stream. The heavy aromatics fractionation column bottoms stream can be sent to other locations, for example, to blend with a gasoline pool if the aromatic compound complex is integrated with a refinery. The other portion of the first xylene column bottoms stream can be sent to reboiler 135 through conduit 435 and returned to first side 405 of split shell fractionation column 430.

[0042] According to one form, the bottoms stream from the reformate side 410 of the split shell fractionation column 430 is sent to a destination other than the transalkylation zone 440. In one approach, as shown in FIG. 4, if the aromatic compound complex is part of a larger refining facility, the reformate side bottom stream is fed through line 436 to the gasoline pool or refining or petrochemical plant. Can be sent to other hydrocarbon streams. Since the bottom _stream mainly contains _{C9 +} aromatics, it is particularly well suited for blending into a gasoline pool. Although not shown, a portion of the reformate side bottom stream can be separated and sent to the reboiler and returned to the reformate side 410 of the split shell fractionation column 430.

[0043] As shown in FIG. 4, an A ₈₊ stream containing isomerized xylenes is processed in an isomerization reactor 162 and separated in a deheptanizer 164. C ₉ aromatics de heptane equalizer column in stream from the isomerization zone usually has a high ratio of methyl / C ₂₊ alkyl-substituted C ₉ aromatics than reformate bottoms stream. In this regard, at least a portion of the deheptanizer bottoms stream can be sent to the first side 405 of the split shell fractionation column 430. In the high energy efficiency complex shown in FIG. 4, the _{deheptanizer bottoms stream} containing C ₈₊ aromatics is discharged through outlet 464 and sent to second xylene fractionation column 133 through conduit 165 and then split. Can be sent to the first side 405 of the shell fractionation column. It was discharged overhead stream comprising C ₈ aromatics can be sent through the line 134 as described above.

[0044] A _{bottoms stream} comprising C ₉₊ aromatic hydrocarbons can be discharged from column 133 through outlet 465. In one approach, at least a portion of the stream is sent through conduit 138 and introduced into split shell fractionation column 430. The bottom stream from the column 133, typically has a concentration of relatively low C ₉ aromatic hydrocarbons than transalkylation stream described above. In this regard, according to one approach, the bottoms stream from column 133 is added to the first side of split shell fractionation column 430 in addition to or instead of the transalkylation zone effluent described above. Part 405 is introduced. In another approach, the bottoms stream from column 133 is introduced into first side 410 of split shell fractionation column 430 in addition to or in place of the reformate stream described above. The bottom stream from the column 133 should be introduced below the upper part of the baffle 433 as well as the upper part of the baffle 433 in the common top region, like the transalkylation zone effluent and reformate stream. Can do. If the bottom stream is sent to one of the first side of the xylene fractionation column and the second side of the column, it can be sent separately through the separate inlets into the column or mixed into a common It can be introduced with other flows through the inlet (examples are shown in FIG. 4). In another approach, at least a portion of the second xylene fractionation column bottoms stream is withdrawn and conduitd, for example, to blend with a gasoline pool if an aromatic compound complex is integrated into the refinery. 437 can be sent elsewhere.

Specific aspects:
[0045] While the above has been described with reference to specific embodiments, it is to be understood that this description is illustrative and is not intended to limit the scope of the above description and the appended claims. Let's go.

[0046] A first aspect of the present invention, separates the first stream comprising xylenes and C ₉ aromatics in a first ratio of methyl groups / phenyl groups, the one side from the other side the containing xylenes and C ₉ aromatics with a second ratio of less methyl groups / phenyl groups than the first ratio; to that sent to one side of the split shell fractionation column comprising a vertical baffle Two streams are sent to the other side of the split shell fractionation column; a common overhead stream containing xylenes is separated from the split shell fractionation column; the first from one side of the split shell fractionation column Separating the second bottom stream; and separating the second bottom stream from the other side of the split shell fractionation column. One aspect of the invention includes one of the more important aspects in this paragraph encompassed by the first aspect in this paragraph, further comprising sending the first bottoms stream as a feed stream to the transalkylation zone, Or all. One aspect of the invention includes any one of the more important aspects in this paragraph encompassed by the first aspect in this paragraph, further comprising recovering at least a portion of the second bottoms stream as a gasoline component. Or all. One aspect of the invention is one of the more important aspects in this paragraph encompassed by the first aspect in this paragraph, wherein at least part of the first stream comprises at least part of the transalkylation zone effluent. , Any or all. One aspect of the invention is any one of the more important aspects in this paragraph encompassed by the first aspect in this paragraph, wherein at least part of the second stream comprises at least part of the reformate stream. Or all. One aspect of the invention is one of the more important aspects in this paragraph encompassed by the first aspect in this paragraph, wherein at least part of the first stream comprises at least part of the isomerization zone effluent. Any or all. One aspect of the invention provides that a portion of the isomerization zone effluent stream is sent to a second xylene fractionation column, wherein at least a portion of the first stream is at least a portion of the bottom stream from the second xylene fractionation column. One, any, or all of the more important aspects in this paragraph that are encompassed by the first aspect in this paragraph. One aspect of the present invention is a more important aspect in this paragraph encompassed by the first aspect in this paragraph, wherein the ratio of methyl / phenyl groups in the first stream is between 1.0 and 4.0. One, any, or all of One aspect of the present invention is a more important aspect in this paragraph encompassed by the first aspect in this paragraph, wherein the ratio of methyl / phenyl groups in the second stream is between 0.5 and 3.5. One, any, or all of

[0047] A second aspect of the present invention, at least a portion of the transalkylation zone effluent stream comprising C ₉ aromatics, including vertical baffle separating the transalkylation effluent stream side from the reformate side a second stream comprising at least a portion of the reformate stream comprising C ₉ aromatics, feeding the reformate side of the split shell fractionation column; transalkylation effluent side feed split shell fractionation column split shell component separating the common overhead stream comprising xylenes from distillation column; C ₉ transalkylation effluent side bottoms stream comprising aromatic compounds is separated from the transalkylation effluent side of the split shell fractionation column; C Separating the reformate side bottom stream containing ₉ aromatic compounds from the reformate side of the split shell fractionation column; It is a method. One aspect of the invention is more important in this paragraph encompassed by the second aspect in this paragraph, further comprising sending at least a portion of the transalkylation effluent tower bottom stream as a feed stream to the transalkylation zone. One, any or all of the aspects. One aspect of the present invention is a more important aspect of this paragraph encompassed by the second aspect of this paragraph, further comprising sending at least 95% by volume of the reformate side bottom stream to a destination other than the transalkylation zone. One, any, or all of One aspect of the invention includes any one of the more important aspects of this paragraph encompassed by the second aspect of this paragraph, further comprising recovering at least a portion of the reformate side bottom stream as a gasoline component. Or all. One aspect of the present invention may further include sending the split shell fractionation column a third stream comprising at least a portion of the isomerization zone effluent stream comprising C ₉ aromatics, to a second aspect of the present paragraph One, any, or all of the more important aspects in this paragraph that are included. One aspect of the invention provides that a portion of the isomerization zone effluent stream is sent to a second xylene fractionation column, wherein at least a portion of the first stream is at least a portion of the bottom stream from the second xylene fractionation column. One, any, or all of the more important aspects in this paragraph that are encompassed by the second aspect in this paragraph.

[0048] A third aspect of the present invention provides a reforming zone comprising a reforming catalyst for reforming one or more hydrocarbon compounds to increase aromatic compounds; C ₇ and C ₉ aromatic compounds; A transalkylation zone containing a transalkylation catalyst for transalkylation; extending upward from the reactor shell and the bottom portion of the split shell fractionation column to a height below the height of the fractionation column; A split shell fractionation column having baffles separated into a first side and a second side; an inlet to the first side of the fractionation column in fluid communication with the outlet of the transalkylation zone; The inlet to the second side of the fractionation column in fluid communication with the outlet of the reforming zone; the top outlet of the fractionation column to discharge the xylene-enriched stream; the bottom side stream of the first side The first side of the fractionation column for discharging A first bottom outlet in body communication; and a second bottom outlet in fluid communication with the second side of the fractionation column for discharging a second side bottom stream; Is a system for producing one or more types of xylenes. One aspect of the present invention is one of the more important aspects of this paragraph encompassed by the third aspect of this paragraph, wherein the first bottom outlet is in fluid communication with the inlet of the transalkylation zone. Or all. One aspect of the invention provides one, any, or all of the more important aspects in this paragraph encompassed by the third aspect in this paragraph, wherein the second bottom outlet is in fluid communication with the gasoline pool. It is. One aspect of the invention includes an isomerization reactor and an isomerization catalyst; and at least one of an inlet to a first side, an inlet to a second side, or another inlet of a split shell fractionation column. One, any, or all of the more important aspects in this paragraph encompassed by the third aspect in this paragraph, further comprising an isomerization section comprising an isomerization section outlet in fluid communication. One aspect of the present invention further includes a second xylene fractionation column between the isomerization zone and the split shell fractionation column, wherein the second xylene fractionation column is in fluid communication with the isomerization zone outlet. An inlet; a top outlet for removing the top stream containing xylenes; and an inlet to the first side for sending the bottom stream from the second xylene column to the split shell fractionation column, second Or more important aspects of this paragraph encompassed by the third aspect of this paragraph, including a bottom outlet in fluid communication with at least one of the inlets to the sides of the column or the other inlets of the split shell fractionation column One, any, or all of

  [0049] Although the invention disclosed herein has been described using specific embodiments, examples and applications thereof, numerous modifications and changes may be made without departing from the scope of the invention as set forth in the claims. Could be done by a vendor.

[0049] Although the invention disclosed herein has been described using specific embodiments, examples and applications thereof, numerous modifications and changes may be made without departing from the scope of the invention as set forth in the claims. Could be done by a vendor.
Specific embodiments of the present invention are as follows.
[1]
A first stream comprising xylenes in first ratio of methyl groups / phenyl and C ₉ aromatics, split shell fractionation comprising vertical baffle separating the one side from the other side Sent to one side of the column;
A second stream comprising xylenes and C ₉ aromatics with a second ratio of less methyl groups / phenyl groups than the first ratio, the feed to the other side of the split shell fractionation column;
Separating a common overhead stream containing xylenes from a split shell fractionation column;
Separating a first bottoms stream from one side of a split shell fractionation column; and
Separating the second bottoms stream from the other side of the split shell fractionation column;
To produce one or more xylenes.
[2]
The method of [1], further comprising sending the first bottoms stream as a feed stream to the transalkylation zone.
[3]
The method according to [1], further comprising recovering at least part of the second bottom stream as a gasoline component.
[4]
The method of [1], wherein at least a portion of the first stream comprises at least a portion of the transalkylation zone effluent.
[5]
The method of [1], wherein at least part of the second stream comprises at least part of the reformate stream.
[6]
The method of [1], wherein at least a portion of the first stream comprises at least a portion of the isomerization zone effluent.
[7]
[6], wherein a portion of the isomerization zone effluent stream is sent to a second xylene fractionation column, and at least a portion of the first stream comprises at least a portion of the bottoms stream from the second xylene fractionation column. The method described.
[8]
The method according to [1], wherein the ratio of methyl group / phenyl group in the first stream is between 1.0 and 4.0.
[9]
The process according to [1], wherein the ratio of methyl group / phenyl group in the second stream is between 0.5 and 3.5.
[10]
A reforming zone containing a reforming catalyst for reforming one or more hydrocarbon compounds to increase aromatic compounds;
Transalkylation zone containing a transalkylation catalyst for transalkylation of C ₇ and C ₉ aromatics;
A reactor shell and a baffle extending upward from a bottom portion of the split shell fractionation column to a height lower than the height of the fractionation column to separate the column into a first side and a second side A split shell fractionation column having:
An inlet to the first side of the fractionation column in fluid communication with the outlet of the transalkylation zone;
An inlet to the second side of the fractionation column in fluid communication with the outlet of the reforming zone;
The overhead outlet of the fractionation column for discharging the xylene-enriched stream;
A first bottom outlet in fluid communication with the first side of the fractionation column for discharging a first side bottom stream; and
A second bottom outlet in fluid communication with the second side of the fractionation column for discharging the bottom side bottom stream;
A system for producing one or more xylenes.

Claims (10)

A first stream comprising xylenes in first ratio of methyl groups / phenyl and C ₉ aromatics, split shell fractionation comprising vertical baffle separating the one side from the other side Sent to one side of the column;
A second stream comprising xylenes and C ₉ aromatics with a second ratio of less methyl groups / phenyl groups than the first ratio, the feed to the other side of the split shell fractionation column;
Separating a common overhead stream containing xylenes from a split shell fractionation column;
Separating a first bottoms stream from one side of the split shell fractionation column; and separating a second bottoms stream from the other side of the split shell fractionation column;
To produce one or more xylenes.   The method of claim 1, further comprising sending the first bottoms stream as a feed stream to the transalkylation zone.   The method of claim 1, further comprising recovering at least a portion of the second bottoms stream as a gasoline component.   The method of claim 1, wherein at least a portion of the first stream comprises at least a portion of a transalkylation zone effluent.   The method of claim 1, wherein at least a portion of the second stream comprises at least a portion of a reformate stream.   The method of claim 1, wherein at least a portion of the first stream comprises at least a portion of the isomerization zone effluent.   7. A portion of the isomerization zone effluent stream is sent to a second xylene fractionation column, wherein at least a portion of the first stream comprises at least a portion of a bottoms stream from the second xylene fractionation column. The method described.   The process according to claim 1, wherein the ratio of methyl groups / phenyl groups of the first stream is between 1.0 and 4.0.   The process of claim 1 wherein the ratio of methyl / phenyl groups in the second stream is between 0.5 and 3.5. A reforming zone containing a reforming catalyst for reforming one or more hydrocarbon compounds to increase aromatic compounds;
Transalkylation zone containing a transalkylation catalyst for transalkylation of C ₇ and C ₉ aromatics;
A reactor shell and a baffle extending upward from a bottom portion of the split shell fractionation column to a height lower than the height of the fractionation column to separate the column into a first side and a second side A split shell fractionation column having:
An inlet to the first side of the fractionation column in fluid communication with the outlet of the transalkylation zone;
An inlet to the second side of the fractionation column in fluid communication with the outlet of the reforming zone;
The overhead outlet of the fractionation column for discharging the xylene-enriched stream;
A first bottom outlet in fluid communication with the first side of the fractionation column for discharging a first side bottom stream; and for discharging a second side bottom stream A second bottom outlet in fluid communication with the second side of the fractionation column;
A system for producing one or more xylenes.

Images